I'm a WD fan, got a Raptor fetish right now
I've had Seagates and Maxtors , Maxtor being the only drive that ever failed on me.
They all did what they were supposed to do, store pr0n and games.
Anyway because of my current fetish I'll say WD FTW.

I think both companies (WD and Seagate) are good companies. Both manufacturers make good HDDs. I would consider either company in a HDD purchase.

I will say this, WD customer support is horrendous. Took me 7 days to get an automated response! It has been about 8 days since the automated response and I have not yet gotten my actual human response (that will be a copy and paste response). Never used Seagate customer support, so I cannot comment on that.